The present invention relates to closure systems and dispensing nozzles for containers for air-curable compositions and is particularly directed toward resealable caulking cartridges.
For many years there have been available caulking guns for providing sealant bonds in building construction or the like. Such guns make use of disposable tubular cartridges which contain a liquid caulking compound or sealant. A piston applies pressure to the rear portion of the cartridge which acts as a piston to force sealant out of a nozzle at the front of the cartridge.
Many modern sealants are designed to cure upon contact with air such as for example by reacting with water vapor in the air to form a rigid or semi-rigid mass to seal the area to which the liquid has been applied. In order to prevent curing of the material in the cartridge prior to use the cartridges are factory sealed and typically a tapered nozzle having a closed end is provided on the cartridge. When made ready for use the nozzle tip is cut off at a point along the taper which provides the desired orifice size for dispensing the sealant.
One of the greatest aggravations to the user of these devices is the inability to reseal the cartridges after partial use, resulting in waste of the remainder of the cartridge. The cut end of the nozzle allows air to enter the exposed sealant causing it to cure first in the nozzle and gradually into the cartridge. To partially alleviate this problem some sealant cartridges are made with threaded necks and a screw-on nozzle having mating threads. After short term storage the nozzle can be unthreaded from the cartridge and the cured plug of sealant pushed out of the back end of the nozzle by pressure applied through the cut off end. However, if curing has progressed beyond the nozzle into the cartridge re-use becomes almost impossible.